The present invention relates to the cutting device which splits a face-to-face woven pile fabric into a top and bottom pile fabric.
The present invention deals more particularly with the components of a cutting device of this kind which determine the opening between the top and bottom cutting rails and the vertical position of the cutter blade in relation to the two cutting rails.
In face-to-face weaving the height of the pile of the woven fabric is determined by various parameters. The most important of these parameters are the following: the ratio of the feed speed of the pile warp threads to the feed speed of the warp threads, the tension on the warp threads, and the adjustment of the jaw, that is to say the height of the opening between the bottom and top cutting rails through which the unseparated face-to-face fabric is guided to the knife blade. If the adjustment of the jaw is not in conformity with the other parameters which also determine the height of the pile, the resulting fabric is of inferior quality.
On the other hand, the equal pile height of the split fabrics is determined, in addition to other parameters, by the positioning of the top and bottom cutting rails in relation to the fixed cutting bank. The top and bottom cutting rails must be disposed in such a manner that the line followed by the tip of the knife blade during the movement of the knife carriage is situated exactly in the middle between and parallel to the two cutting rails. If this requirement is not met, the height of the pile may be different in each of the pile fabrics produced and/or may vary over the width of the resulting pile fabrics.
Up to the present time the bottom and top cutting rails have been adjusted manually with the aid of set screws and adjusting nuts. Adjustment can be made only by a trial and error method and can be checked only by weaving a few meters, measuring the pile height of the two pile fabrics produced at a number of points and, if the pile heights are not equal, amending the adjustment of the two cutting rails. This procedure must sometimes be repeated several times before the correct adjustment is obtained. Not only did this mean spending a considerable time on adjustment, but also resulted in the production of many meters of second grade pile fabric.